"Use this 12ft.L canvas tube to deliver indirect-fired preheated air from space heaters to various temporary and permanent shelters. Handles air temperatures from -60F to 300F. Canvas is treated to resist mildew, rot, water and flames and a heavy-duty fiberglass liner provides added protection from heater burnout. Works with EcoBlaze Indirect Space Heater Item numbers 700070 and 700071. Mounting Hardware Included Yes, Adjustable Yes, Length in. 144, Material Type Canvas, Pieces qty. 1, Product Style Flexible ducting, Fuel Type Diesel burning, Pipe Design Single wall, Pipe Diameter in. 12. Kevlar stitching is rated to 1000F Wire reinforced to prevent collapsing and support bends"